10. The necessity for eliminating the little overlooked clues and loose threads
8. The cover up
7. The flight
6. The actual killing
5. The first irretrievable step
4. The opportunity
3. The plan
The False Suspect is more a convention of taste and times when it appeared. A False Suspect is useful, but could also be an unnecessary plot elaboration.
The type of murderer that climbs past this rung in the ladder probably wouldn’t miss it. However, an insecure murderer might be at a loss.